Die clamp



Nov. 26, 1963 l Filed July 13, 1961 D. H. KRAr-r ETAL 3,111,895

. DIE CLAMP 5 Sheets-Sheet 1 TORNEYS Nov.26, 1963 D. H KRAFT ETAL 3,111,895

lDIE: CLAMP Filed July 1s, 1961 s'sneets-sheet 2 INVENTORS DERALD H. KRAFT 8 DOUGLAS W. HITCHINGS ATTORNEYS Nov'. 26, 1963 D. H. KRAFr ETAI. 3,111,395

DIE CLAMP Filed July 13, 1961 5 Sheets-5h66?. 3

38 F IG. 3 (Loom I6 2 se F I G. 4

(UNLOGK) INVENTRS DERALD H. KRAFT 8 BY DOU'GLAS W. HITCHINGS TTORN EYS Nov. 26, 1963 n. H. KRAFT ETAL 3,111,895

DIE (JLM/u` Filed July 13, 1961 5 Sheets-Sheet 4 FIG. e K

TORS. H. AFT 8s 8 BDOUGLAS W. HITCHINGS KR l2 UWM* ATTO NEYS Nov. 26, 1963 D. H. KRAFT ETAL DIE CLAMP 5 Sheets-Sheet 5 Filed July 13, 1961 FIG. 7

Alu F INVENTORS DERLD H. KRAFT a BYDOUGLAS W. HITCHINGS www,

' TTORNEYS United States Patent 3,111,895 DIE CLAMP Derald H. Kraft and Douglas W. Hitchings, both of Canton, Ohio, assignors to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Juy 13, 1961, Ser. No. 123,803 17 Claims. (Cl. 100 295) This invention relates to means for securing diesl to presses, and more particularly to means relating to quickacting clamping and unclamping mechanisms for securing dies to the slide and bolster plates of presses.

This application is a continuation-in-part of our co pending application Serial No. 825,731, led August 8, 1959, now abandoned and assigned to the yassignee of the present application.

In conventional practice, the die members for use in presses are provided with T-slots adjacent the face of the die `abutting the press slide or bolster plate. A plurality of bolt holes are usually provided in the slide or bolster plate to receive bolts therethrough, the heads of which are placed in engagement with the T-slots of the dies. Thus, by threading nuts onto the ends of the bolts projecting through the slide or bolster plate, the heads of the bolts are drawn into contact with the T-slots of the dies, thereby clamping the dies to the adjacent faces of the slide and bolster plates. The number of bolts required to securely fasten the dies to the press is, of course, dependent upon the size and weight of the dies; but in any event, the operation of manually fastening dies to the slide and bolster plates of the press is slow and inefficient.

It is, therefore, among the objects of our invention to provide means for clamping dies to the slide and bolster plates of a press which is automatic, quick-acting, failsafe, and universal in adaptability with respect to dimensional specifications for most dies.

To the accomplishment of the foregoing objects and related ends, the invention consists of the means hereinafter ful-ly described `and particularly pointed out in the claims, the annexed drawings, and the following description, setting forth in detail certain structure embodying 4the invention, such disclosed means constituting, however, but one of the various forms in which the principle of the invention may be used.

With reference to the drawings:

FIGURE l is a perspective view of a press and its associated dies employing the clamping means of the invention;

FIGURE 2 is a cross-sectional view of one of the upper clamping units employed to secure a die to the press slide;

FIGURE 3 is a cross-sectional view taken along line 3 3 of FIGURE 2 illustrating the rotational stop means of the upper clamping unit in the locked position;

FIGURE 4 is a cross-sectional View similar to FIG- URE 3 but with the clamping member of the upper clamping unit rotated 90 from that position shown in FIG- URE 3;

FIGURE 5 is a cross-sectional View taken along line 5 5 of FIGURE 2 showing the clamp engaging head of the upper clamping unit in engagement with the T-slot of a die adapted for connection to a press slide;

FIGURE 6 is an elevational view of one of the lower clamping devices for the press bolster plate, partially in section and with parts broken away to illustrate the relationship between the various elements;

FIGURE 7 is a cross-sectional view taken along line 7 7 of FIGURE 6 illustrating the manner in which the rotational stop means of the lower clamping device for the press bolster plate may be rotated and retracted into the bolster plate;

FIGURE 8 is a cross-sectional view taken along Iline 8 8 of FIGURE 6 illustrating the recess in the press bolster plate into which the rotational stop means of the lower clamping unit may be retracted;

FIGURE 9 is a cross-sectional view taken along line 9 9 of FIGURE 6; and

FIGURE l0 is a cross-sectional View taken along line 10 10 of FIGURE 6.

Referring now to the drawings, and particularly to FIGURE l, a press is shown having a reciprocable upper slide plate 2, a lower stationary bolster plate 4, and dies 6 and 8 adapted to be secured to the slide plate 2 and bolster plate 4, respectively. In accordance with the present invention, improved die clamping units 10A and 10B are provided on the slide plate 2 for securing the die 6 to the slide plate; and, in a similar manner, clamping units 11A and 11B are provided below the bolster plate 4 for securing die 8 to the bolster plate.

Referring to FIGURE 2, the clamping unit 10A, for example, is seen to comprise an elongated, cyclindrical shaft 36 having a T-shaped head 12 (see also FIGURE 5) on one end and a threaded shaft portion 14 on the opposite end. A housing 16 encases the upper mid-portion of the shaft 36 and the housing top surface 18 provides a shoulder upon which a threaded collar or nut 20 rests in threaded engagement with the threaded shaft portion 14. A recessed or socket-type adaptor 22 is secured to the shaft 24 of motor means 26 by a pin 25 and is adapted to engage the nut 20. Preferably, the motor means 26 comprises an air motor or other similar device. It will be observed that the adaptor 22 is elongated to permit sliding movement of the nut 20 therein. The T-shaped head 12 may be adjusted manually by application of a wrench to the squared portion 27 on socket 22.

Stop means comprising a set screw 28 and a nut 30 lare threadedly engaged in the housing 16 to alternately make engagement with the shoulder 32 or shoulder 34 (see FIGURES 3 and 4) formed by recessing the midportion of the shaft 36. The 1recessed portion 38 is elongated to permit sliding movement of the shaft 36 within the housing 16. A limit switch 40 is also mounted in the housing 16 and adapted to be tripped by movement of a ball 42 either into or out of a longitudinally elongated recess or groove 44 machined in the shaft 36' (see also FIGURE 4).

As will be seen in FIGURES 3 and 4, the set screw 28 and the elongated slot 38 providing shoulders 32 and 34 permits rotation through 90 from one shoulder t0 the other shoulder. In so rotating the clamping member from one shoulder to the other shoulder, it will be observed that lthe position of the head 12 `of the clamping member is shifted to and from clamping relationship with the shoulders 46 and 48 of the T-slot 50 in the die member 6, or in the alternate position for free movement through the narrow slotted portion 54 of tht T-slot 50. The limit switch 40 may be employed to close circuitry which will provide a visual indication of the position of the T-head 12 or, in the alternative, may be employed to render the press inoperable for production unless the T-head 12 of the clamping means 10a is in the position shown in FIGURE 3. Under these circumstances, the groove 44 is positioned so that the ball 42 will seat only when the T-head 12 is in the proper angular relationship with the T-slot 50. Any rotational movement of the clamping member shaft 36 from Ithe position of FIG- URE 3 will cause the ball 42 to ride out of the groove 44, thereby tripping the limit switch -to activate the safety means provided to indicate and/or respond to this condition.

Referring again to FIGURE 1, it will be seen that the lower portion of upper clamping unit 10A is adapted to be tted into a hole 60 in the slide plate 2 of the press, and that the hole is provided with a counter-bore 64 of sumcient size to completely contain therein the T-head 12 of the clamping member (see also FIGURE 2). Overriding clutch means 65 (FIGURE 2) comprising a helically coiled spring 66 and the spring pads 68 and 70 on opposite ends thereof are tted to abut against a tapered portion 72 of the shaft 36 and corresponding tapered portion 74 of the nut 20, respectively. The pressure exerted between the tapered portion 72 and the nut portion 74 by the coiled spring 66 is suflicient to cause the nut 20 and the shaft 36 to be rotated in unison until engagement is made between the stop member 28 and one of the shoulders 32 or 34 of the clamping member. Thereafter, the over-riding clutch will slip if continued rotation of the nut is transmitted by the motor means 26, to either lower or raise the clamping member 36 relative to the die and/or slide plate 2. Thus, it will be seen that the lower portion of the shaft 36 is free to slide within the hole 60 in the slide plate 2, and the upper portion of the shaft, including threaded portion 14, is free to move within the housing 16 and the adaptor 22.

The significance of this sliding arrangement will be readily appreciated upon considering the means for securing the upper die 6 to the slide plate 2. The slide 2 of the press is lowered toward the die 6, which is set up beneath the slide until contact is made between the abutting faces 80 and 82 of the slide and die, respectively. However, in order for clamping engagement to be made, it is necessary that the required orientation of the clamping member T- head 12 exists such as is shown in FIGURE 4 so that the T- head may pass freely through the slot 54 of the die 6. In the event that the T-head should be at some random orientation, i.e., in any position other than that shown in FIG- URE 4, then the T-head will strike the top face 82 of the die when the slide 2 is lowered into contact with the die 6. However no harm will corne from this engagement of the T-head 12 with the die face 82 inasmuch as the shaft 36 is free to slide vertically upwardly and the T-head 12 will be received within the counterbore 64 of the slide 2 expressly provided for this purpose. From this it is apparent that one function of the elongated adaptor 22, which acts in the nature of a lost motion coupling, is to permit movement up and down as necessary in the event of interference between parts while adjustment is being made between the slide plate 2 and the die 6. To this end, longitudinal slot 38 and groove 44 also coact with the adaptor 22 to permit vertical movement of the shaft 36. Additionally, of course, it provides for power adjustment of the clamping member 12 by motor 26.

In the operation of the upper die clamping units A and 10B, the clamping members 12 are adjusted to the correct length before the slide 2 is lowered into contact with the die 6, and the heads 12 of the clamping members are properly oriented as shown in FIGURE 4, and as discussed hereinabove. The slide 2 is then lowered into contact with the die 6, and the individual motors 26 may be operated to finally adjust the clamping members down, if necessary. Thereafter, motors 26 are driven to align the T-heads into clamping positions as shown in FIGURE 3. The coaetion between the over-riding clutch 65, stop means 28, and the shoulders 32 and 34 will automatically obtain the proper T-head-T-slot orientation. Once proper orientation is obtained between the shoulders 46 and 48 and the T-head 12 of the clamping member 10, the ball 42 of the limit switch 40 will seat in the groove 44 of the shaft 36, thereby tripping limit switch 40 to indicate proper orientation. The actual indication may be either visual on by actuating circuit enabling means, or both. Concurrently, motor 26 continues to back head 12 into clamping engagement with the shoulders 46 and 48, and thereafter motor 26 will stall or torque out when clamping engagement has been made. Suitable motor cut-off means may be provided to deactivate the motor after clamping engagement.

Referring now to FIGURES 6 and 7, the lower clamping unit 11A, for example, is provided with a T-head 90, similar to T-head 12, adapted to fit into a cooperating T-slot 92 provided in the lower die 8. As was the case with the clamping unit 10A, the head 90 is adapted to be shifted to and from clamping relationship with shoulders 94 and 96 of the T-slot 92 in the die member 8, or in the alternate position for free movement through a narrow slotted portion 98 of the T-slot 92. The alternate positions of the T-head are illustrated in FIGURE 7 where the clamping position of the head is shown in full lines while the retracted position is shown in dotted lines. While retracted, the head engages a seat 99 (FIG- URES 7 and 8) in the bolster plate 4. In order, then, to effect clamping of the die 8 to bolster plate 4 it is necessary to raise the head 90 and rotate it through 90 as was the case with clamping units 10A and 10B.

Integral with the T-head 90 is a shaft 100 which extends through a slot 102 in the bolster plate 4 and down into a housing 108 for the clamping unit proper. Suitable fastening means, such as bolts 104 and 106 are employed to secure the housing 108 for the clamping unit to the bolster block 4, substantially as shown. The lower end of the shaft has a reduced diameter portion 110 which is threaded to receive a hexagonal nut 112 (see also FIGURE l0), this hexagonal nut being received within a cooperating hexagonal bore 114 provided in a rotatable cylindrical member 116. The cylindrical member 116 rotates about a vertical axis between bushing 118 at the top of the unit and a ball bearing 120 which cooperates with an annular bushing 122 at the bottom of the assembly. Secured to the bottom of the cylindrical member 116 is a spur gear 124 which meshes with a second spur gear 126 secured to the bottom of the shaft 128 of air motor means 130 which may incorporate over riding clutch means similar to clutch means 65 shown in FIGURE 2. Thus, when the air motor 130 rotates in one direction, the cylindrical member 116 will rotate the nut 112 to lower the shaft 100 and T-head 90; while rotation of the air motor 130 in the opposite direction will rotate the cylindrical member 116 and nut 112 to elevate the shaft and T-head until the nut 112 engages a second nut 132 threadedly received on the lower end of the shaft 100. As will be understood, the arrangement of the spur gears 124 and 126 enables the air motor 130 to be doubled back along the housing 108 to thereby shorten the overall length of the unit.

Provided in the reduced diameter portion 110 of shaft 100 is a transversely-extending bore 134 which receives a coil spring 136 interposed between a pair of button-shaped resilient members 138 and 140. The purpose of the members 138 and 140 is to engage the threads of the nut 112 and provide a frictional drag between the nut and the threaded portion 110 and prevent free or uncontrolled rotation of shaft 100 and the T-head 90 connected thereto.

Intermediate the ends of the shaft 100 is an enlarged diameter portion 142 which forms an annular cavity 144 between the inner periphery of the bore 146 in housing 108 and the periphery of shaft 100 between portions 142 and 110. At the lower end of portion 142 is a groove 148 which receives an O-ring seal 150 for a purpose which will hereinafter be explained. Communicating with the annular passageway 144 is a threaded opening 152 adapted to be selectively connected to a source of uid under pressure not shown.

It will be appreciated that in the case of clamping units 10A and 10B, the T-heads 12 and shafts 36 will drop into the slots 54 and 50 by gravity; while the T-heads 12 can be removed from the slots 50 and 54 by merely elevating the slide plate 2. In the case of the lower clamping units 11A and 11B, however, these conditions do not exist so that it is necessary to forcibly raise the shaft 100 and T-head 90 to move it through slot 98 and into the T-slot 92. For this purpose, fluid under pressure is introduced into the annular passageway 144 through opening 152,

whereupon the uid will act upon shoulder 153 below the O-ring 150 to force the shaft 100 and T-head 90 carried thereby upwardly. In order to lower the shaft 100 and T-head 90, the air pressure is released whereby the shaft and T-head may fall downwardly by gravity, assuming that the T-head is properly oriented with respect to slot 9S to permit it to pass therethrough (i.e., in the position shown in dotted outline in FIGURE 7). By virtue of the elongated hexagonal opening provided in the cylindrical member 116, the nut 112 may simply slide upwardly or downwardly within the bore, as the case may be. In this respect, the member 116 provides a lost motion coupling similar to that provided by adaptor 22 in FIGURE 2.

Referring now to FIGURES 6 and 9, it will be noted that the enlarged diameter portion 142 of shaft 100 has three slots 154, 156 and 158 provided in its outer periphery. Slots 154 and 158 are adapted to cooperate with balls 160 and 162, respectively, carried in the wall of housing 108. The balls 160 and 162, in turn, are adapted to actuate limit switches 164 and 166, respectively, these limit switches being carried within a housing 167. The slot 156, on the other hand, cooperates with a stop means comprising a set screw 168 and a nut 170 threadedly engaged therewith. It will be noted that the slot 156 is provided with an upper, axially-extending portion 156a which communicates with a lower arcuate portion 156b extending around the shaft 100 for about 90. Thus, when the shaft 100 and T-head 90 are in the elevated position shown in FIGURE 6, they may rotate through 90 while the forward end of the set screw 16S extends into the lower, arcuate portion 15611 of slot 156. In order to lower the shaft 100, however, the T-head 9i) must be rotated through 90 from the position shown in FIGURES 6 and 7. Under these circumstances, the forward end of the set screw 168 will extend into the axially-extending portion 156a of the slot 156 to permit the shaft 100 to move downwardly. Once the end of the set screw 168 enters portion 156e, the shaft 100 can no longer rotate, but it can move upwardly or downwardly.

The slot 154 extends through an are of substantially 90 on the side of shaft 100 opposite the slot 156. Whenever the shaft 100 is elevated into the position shown in FIGURE 6, the slot 154 will permit the ball 160 to move inwardly, thereby tripping limit switch 164. Furthermore, the limit switch 164 will remain tripped even though the shaft 100 is rotated through 90 in a clockwise direction from the position shown in FIGURE 9. The slot 158, however, extends for only a short distance circumferentially around the shaft 100 and will engage the ball 162 to trip limit switch 166 when, and only when, the shaft 100 is rotated into the position shown in full lines in FIG- URES 6 and 7. That is, the limit switch 166 will be tripped only when the shaft 100 has been elevated and rotated through 90 such that set screw 168 extends into the lower circumferentially-extending portion of the slot 156 and the T-head 90 is in clamping position.

In the operation of the lower clamping unit 11A, for example, the shaft 100 will initially be in the dotted line position shown in FIGURE 7, at which time the T-head 90will extend into the slot 102 provided therefor in the bolster plate 4. In order to raise the shaft 100, a valve, not shown, is opened to admit uid under pressure into the annular passageway 144 through opening 152, thereby raising the shaft 100 and T-head 90 to the proper height. During this time, the forward end of the set screw 168 slides within the axially-extending portion 156a of slot 156. As soon as the shaft 100 reaches the proper height, the slot 154 will reach ball 160 whereby the limit switch 164 is tripped. When limit switch 164 is tripped, circuitry, not shown, actuates the air motor 130 to rotate spur gears 126 and 124 as well as the cylindrical member 116. The action of the motor causes the shaft 100 to rotate in a counterclockwise direction as viewed in FIG- URES 8, 9 and l0, whereby the forward end of set screw 168 will move into the lower circumferentially-extending portion of slot 156 until it engages a shoulder 189 (FIG- URE 9). When the forward end of set screw 163 engages shoulder 180, the slot 158 will register with ball 162 to trip limit switch 166. Limit switch 166, in turn, actuates an indicating means to signal the operator that the shaft 100 and T-head 90 have been rotated to the proper locking position. Thereafter, the air motor 130 continues to rotate the cylindrical member 116 and the nut 112 whereby the T-head is tightened against shoulders 94 and 96 to securely clamp the die 8 to the bolster plate 4. This action will continue until a maximum torque is obtained and the motor stalls or torques out. As was the case with motors 26, suitable motor cut-off means may be provided to de-activate the motor after clamping engagement.

In order to release the clamp, the motor 130` is rotated in the opposite direction to rotate the cylindrical member 116 and nut 112 in a clockwise direction as viewed in FIGURE 10. Initially, the nut 112 will rotate while the shaft 100 remains stationary until the T-head 90 is loosened. Thereafter, continued rotation of the nut 112 in a clockwise direction Iwill cause the shaft 100' and T-head 90 to rotate in a clockwise direction also as viewed in FIGURES 8 and 9 until the set screw 16S engages a side of the axially-extending portion 156e of slot 156. At this point, the T-head 90 will have been rotated into position whereby it may fall through the slot 98 and into slot 102 in bolster plate 4 where it comes to rest against seat 99. As the shaft 100 drops down, it resets the limit switch 164 to cut off the air motor 130. The die 8- may thereafter be easily removed from the bolster plate 4.

Although the invention has been shown in connection with certain specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of Iparts may be made to sui-t requirements without departing from the spirit and scope of the invention.

We claim:

l. In combination with a press having a die-receiving member and a die having a T-slot therein with shoulders in the T-slot adapted to be engaged by a clamping member; the improvement in means to secure said die to said die-receiving member comprising a clamp-ing member having a T-.head on one end adapted to enter said T-slot when in a predetermined oriented position and to engage the shoulders of said T-slot when rotated 90 from said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said diereceiving member adapted to contain auch of said shank portion extending beyond said passageway, stop means secured to said housing and stop means located on said shank portion to establish said oriented position when rotated into contact with said housing stop means, second stop means located on said shank portion to establish a position 90 from said oriented position when counterrotated into contact with said housing stop means, limit switch means secured in :said housing, means on said shank portion adapted to trip said limit switch means when said T-head is in T-slot shoulder engaging position, a shoulder on said housing, a nut adapted to rest on said shoulder and engage the threaded portion of said shank, and drive means to rotate said nut.

2. The combination claimed in claim l and including over-riding pressure means interposed between said nut and said shank portion.

3. The device set forth .in claim 1, in which a recess is provided in said die-receiving member adapted to receive said T-head therein, and a lost motion coupling interposed between said drive means and said nut to permit axial sliding movement of said clamping means through said passageway.

4. In combination with a press having a die-receiving member and a die having a T-slot therein with shoulders adapted to `be engaged by a clamping member; the improvement in means to secure said die to said die-receiving member comprising a clamping member having a T- head on one end adapted to enter said T-slot when in a predetermined oriented position and to engage the shoulders of said T-slot when rotated 90 from said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, stop means secured to said housing and stop means located on said shank portion to establish said oriented position when rotated into contact with said housing7 stop means, second stop means located on said shank lportion to establish a position 90 from said oriented position when counter-rotated into contact with said housing stop means, a shoulder on said housing, a nut adapted to rest on said shoulder and engage the threaded portion of said shank, and drive means to rotate said nut.

5. A press die clamp of the class described compris-ing a clamping member having a T-head on one end adapted to engage -a T-slot of a die, a shank portion on the opposite end of said clamping member, a housing to contain the shank portion of said clamping member, stop means secured to said housing to `limit rotational movement of said clamping member, over-riding clutch means drivingly connected to said clamping member, and means coacting with said clutch means to rotate said clamping member into contact with said stop means.

6. A press die clamp of the class described comprising a clamping member having a T-head on one end adapted to engage a T-slot of a die, a threaded shank portion on the opposite end of said clamping member, a housing to contain the shank portion of said clamping member, stop means secured to said housing to limit rotational movement of said clamping member, a collar threadedly engaged with said threaded shank portion and adapted to bear against said housing, and pressure means in slipclutch driving engagement `between said collar and said shank portion whereby rotation of said collar coacting with said pressure means rotates said clamping member into contact with said stop means.

7. The device set forth in claim 6, wherein said pressure means comprises a helical spring adapted to exert limited axial pressure between said shank portion and said collar, whereby torque applied to said collar is transmitted by said helical spring means to said shank portion.

8. A press die clamp of the class described comprising a clamping member having a T-head on one end adapted to engage a T-slot of a die, a threaded shank portion on the opposite end of said clamping member, a housing to contain the shank portion of said clamping member, stop means secured to said housing to limit rotational movement of said clamping member, ia collar threadedly engaged with said threaded shank por-,tion and adapted to bear against said housing, limit switch means secured in said housing, and means on said shank portion adapted to trip said limit switch means when said clamping member is rotated into contact with said stop means and to reset the limit switch means when said clamping member is rotated away from said stop means.

9. A press die clamp of the class descnibed comprising a clamping member having a T-head ion one end adapted to engage a T-slot of a die, a threaded shank portion on the opposite end :of said clamping member, a housing to contain the shank portion of said clamping member, stop means secured to said housing to limit rotational movement :of said clamping member, a collar threadedly engaged with said threaded shank portion and adapted to bear against said housing, pressure means in engagement between said collar and said shank portion whereby rotation of said collar coacting with said pressure means rotates said clamping member" into contact with said stop means, limit switch means secured in said housing, and means located on said shank portion to trip said limit switch means upon completion of rotation of said clamping means into engagement with said stop means.

l0. In combination with a press having a die-receiving member and die having a T-slot therein with shoulders adapted to be engaged by a clamping member; the improvement in means to secure said die to `said die-receiving member comprising a clamping member having a T-head on one end adapted to enter said T-slot when in a predetermined oriented position and to engage the shoulders of said T-slot when rotated trom said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, limit switch means secured in said housing, and means on said shank portion adapted to trip said limit switch means when said T-head is in T-slot shoulder engaging position.

ll. In combination with a press having a die-receiving member and a die having a T-slot therein with shoulders adapted to be engaged by a clamping member; the improvement in means to secure said die to said die-receiving member comprising a clamping member having a T-head on one end adapted to enter said T-slot when in a predetermined oriented position, and to engage the shoulders :of said T-slot when rotated from said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, a shoulder on said housing, a nut adapted to rest on said shoulder and engage the threaded portion of said shank portion, drive means to rotate said nut, and a lost motion coupling interposed between said drive means and said nut adapted to permit axial sliding movement of said clamping means through said passageway.

l2. In combination with a press having a die-receiving member and die having ya T-slot therein with shoulders Iadapted to be vengaged by a clamping member; the improvement in means -to secure said die to said die-receiving member comprising -a clamping member having a T-head on one end adapted to enter said T-slot when in a predetermined oriented position, and to engage the shoulders of said T-slot when rotated from said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, limit switch means secured in said housing, means on said shank portion adapted to trip said limit switch means when said T-head is in T-slot shoulder engaging position, a shoulder on said housing, a nut adapted to rest ion said shoulder and engage the threaded portion of said shank, drive means to rotate said nut, and a lost motion coupling interposed between said drive means land said nut adapted to permit axial sliding movement of said clamping means through said passageway.

13. The combination claimed in claim l2 and including `over-riding pressure means interposed between said nut fand said shank portion.

14. In combination with a press having a die-receiving mem-ber and ia die having a T-slot therein with shoulders adapted to be engaged by a clamping member; the improvement in means to secure said die to said die-receiving member comprising a clamping member having a at sided T-head on one end adapted to axially enter said T-slot when in a predetermined oriented position and to :engage the shoulders of said T-slot when rotated from said oriented position, a threaded shank pontion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank pontion to pass axially therethnough, a housing secured to said die-receiving member adapted to contain such of said shank poration extending beyond said passageway, a shoulder on said housing, a nuit adapted lto rest on said shoulder and engage the threaded portion of said shank, and means for motating said nut for forcing said T-head axially through said passageway and into said T-slot when the T-head is in said predetermined oriented position.

15. In combination with a press having a die-receiving member and a die having a T-slot therein with shoulders adapted to be engaged by a Iclamping member; the improvement in means to secure sa-id die lto said die-receiving member comprising a clamping member having a T-head on one end adapted to `enter said T-slo't ywhen in a predetermined oriented position Iand to engage the shoulders of said T-slot when rotated 90 from said oriented position, a threaded shank portion on the opposite end of said clamping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrough, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, Huid pressure means for lforcing said T-head through said passageway and into said T-slot when the T-head is in said predetermined oriented position, stop means secured to said housing and stop means located on said shank portion to establish said oriented position when rotated into Contact with said housing stop means, second stop means located on said shank portion to establish a position 90 from said oriented position when counter-rotated into contact with said housing stop means, a shoulder on said housing, a nut adapted to rest on said shoulder 'and engage the threaded portion of said shank, and drive means to rotate said nut.

16. The device as set forth in claim and including limit switch means secured in said housing and adapted to actuate said drive means, and means on said shank portion adapted to trip said limit switch means to actuate the drive means when said T-head extends into said T-slot.

117. In combination with a press having a die-receiving member `and a die having a 'T-slot therein with shoulders adapted to `be engaged by a clamping member; the improvement in means to secure said die to said slide comprising a clamping member having a T-head on one end adapted to enter said T-s-lot when in a predetermined oriented position and to engage the shoulders of said T- slot lwhen rotated from said oriented position, a threaded shank portion on the opposite end off said clam-ping member, a passageway in said die-receiving member adapted to permit said shank portion to pass therethrou-gh, a housing secured to said die-receiving member adapted to contain such of said shank portion extending beyond said passageway, stop means secured to said housing .and stop means located on said shank portion to establish said oriented position when rotated into contact with said housing stop means, second stop means ylocated on said shank portion to establish a position 90 lfrom said oriented position when counter-rotated into contact with said Ihousing stop means, Irst limit switch means secured in said housing, means on said shank portion adapted to trip said iirst limit switch means when said T-head is in T-slot shoulder engaging position, a shoulder on said housing, a nut adapted to rest on said shoulder and engage the threaded portion of said shank, drive means to rotate said nut, second limit switch means secured in said housing and `adapted to actuate said drive means to rotate said nut, and means on said shank portion adapted to trip said second limit switch means when the T-head extends into said T-slot.

References Cited in the le of this patent UNITED STATES PATENTS 335,092. Robinson Jan. 2,6, 1886 y1,327,011 Arndt Jan. 6, 1920 1,876,237 Jackson Sept. 6, 1932 2,970,855 Fisher Feb. 7, 1961 2,984,176 Sommer et al. May 16, 1961 FOREIGN PATENTS 576,413 France May 13, 1924 589,604 France Feb. 25, '1925 

17. IN COMBINATION WITH A PRESS HAVING A DIE-RECEIVING MEMBER AND A DIE HAVING A T-SLOT THEREIN WITH SHOULDERS ADAPTED TO BE ENGAGED BY A CLAMPING MEMBER; THE IMPROVEMENT IN MEANS TO SECURE SAID DIE TO SAID SLIDE COMPRISING A CLAMPING MEMBER HAVING A T-HEAD ON ONE END ADAPTED TO ENTER SAID T-SLOT WHEN IN A PREDETERMINED ORIENTED POSITION AND TO ENGAGE THE SHOULDERS OF SAID TSLOT WHEN ROTATED 90* FROM SAID ORIENTED POSITION, A THREADED SHANK PORTION ON THE OPPOSITE END OF SAID CLAMPING MEMBER, A PASSAGEWAY IN SAID DIE-RECEIVING MEMBER ADAPTED TO PERMIT SAID SHANK PORTION TO PASS THERETHROUGH, A HOUSING SECURED TO SAID DIE-RECEIVING MEMBER ADAPTED TO CONTAIN SUCH OF SAID SHANK PORTION EXTENDING BEYOND SAID PASSAGEWAY, STOP MEANS SECURED TO SAID HOUSING AND STOP MEANS LOCATED ON SAID SHANK PORTION TO ESTABLISH SAID ORIENTED POSITION WHEN ROTATED INTO CONTACT WITH SAID HOUSING STOP MEANS, SECOND STOP MEANS LOCATED ON SAID SHANK PORTION TO ESTABLISH A POSITION 90* FROM SAID ORIENTED POSITION WHEN COUNTER-ROTATED INTO CONTACT WITH SAID HOUSING STOP MEANS, FIRST LIMIT SWITCH MEANS SECURED IN SAID HOUSING, MEANS ON SAID SHANK PORTION ADAPTED TO TRIP SAID FIRST LIMIT SWITCH MEANS WHEN SAID T-HEAD IS IN T-SLOT SHOULDER ENGAGING POSITION, A SHOULDER ON SAID HOUSING, A NUT ADAPTED TO REST ON SAID SHOULDER AND ENGAGE THE THREADED PORTION OF SAID SHANK, DRIVE MEANS TO ROTATE SAID NUT, SECOND LIMIT SWITCH MEANS SECURED IN SAID HOUSING AND ADAPTED TO ACTUATE SAID DRIVE MEANS TO ROTATE SAID NUT, AND MEANS ON SAID SHANK PORTION ADAPTED TO TRIP SAID SECOND LIMIT SWITCH MEANS WHEN THE T-HEAD EXTENDS INTO SAID T-SLOT. 